From Szent István Bazilika bus to Budapest then bus to Belgrade. 6hrs 45min RSD 3152. From Budapest-Keleti train to Beograd. 7hrs 57min RSD 2056. From Budapest rideshare to Beograd. 4hrs 38min RSD 1944. From Budapest drive to Belgrade. 3hrs 37min RSD 7123. From Budapest-Nyugati train to Ferihegy vasútállomás, bus to Budapest airport, fly to Belgrade airport, then bus to Belgrade. 2hrs 54min RSD 13505. From Budapest shuttle to Belgrade. 5hrs 00min RSD 3099.